Shape member manufacturing apparatus and shape member manufacturing method

ABSTRACT

The invention provides a shape member manufacturing apparatus and a shape member manufacturing method which aims at cutting and grinding a joint projection  8 B formed when a plurality of shape members are joined together by welding or friction stir welding, in a short time with high accuracy.  
     A plurality of mounts  11  having a side structure  8  placed thereon are arranged in the longitudinal direction of the side structure. A joint projection  8 B of a welded portion or a friction stir welded joint is formed on the surface of the side structure  8  in its longitudinal direction. A carrier  100  travels in the longitudinal direction of the side structure  8.  Columns  105  are installed in a girder  103  of the carrier, and a milling cutter device  80  and a grinding device  90  are installed in lower portions of the columns  105.  A milling surface of a milling cutter  81  of the milling cutter device  80  has a circular-arc shape with a radius R. The milling cutter  81  performs cutting at an angle θ1 tilted with respect to a vertical line. Further, the milling cutter device is provided with sliding plates  85 . The milling cutter device performs cutting with the sliding plates  85  brought into contact with the surfaces of the extruded shape members.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional application of U.S. application Ser.No. 11/074,685, filed Mar. 9, 2006, the contents of which areincorporated herein by reference.

The present application is based on and claims priority of Japanesepatent applications No. 2004-272721 filed on Sep. 21, 2004, and No.2005-056092 filed on Mar. 1, 2005, the entire contents of which arehereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the invention

The present invention relates to a shape member manufacturing apparatusand a shape member manufacturing method capable of removing a jointprojection remaining on the surfaces of the shape members to manufacturethe surfaces of the shape members smoothly when a plurality of shapemembers are joined together by welding, friction stir welding, and thelike.

2. Description of the related art

The shape members to be manufactured by the shape member manufacturingapparatus include, for example, extruded shape members made of aluminumalloy (hereinafter simply referred to as extruded shape members). Theextruded shape members include, for example, ones having a flatplate-shaped shape member or a hollow shape member with ribs. Inaddition, the shape member manufacturing apparatus is manufactured tohave a structure, which is obtained by making flat plates abut on eachother and joining them together by welding. There are a structural bodyof a railway car as such manufactured from the extruded shape members.The structural body of a railway car is constructed with an underframe,side structures, a roof structure, and end structures. The sidestructure is manufactured by arranging a plurality of extruded shapemembers with their extruded direction extending along the longitudinaldirection of the side structure, and by arranging the extruded shapemembers in the widthwise direction of the side structure for joiningthem together. The plurality of extruded shape members arranged in thewidthwise direction of the side structure are joined together by weldingor friction stir welding of abutting portions thereof. The roofstructure or the underframe is manufactured almost in the same way asthe side structure. When the adjacent extruded shape members are weldedto each other, MIG welding is generally adopted, and welding beadsprotruding from the surfaces of the extruded shape members are formed atjoints. Further, when the adjacent extruded shape members are joinedtogether by the friction stir welding, projections are previously formedon the surfaces of joints of the respective extruded shape members, andthe projections of both the abutting shape members are joined togetherby a tool for friction stir welding. The projections of both theabutting shape members are partially cut away by the tool for frictionstir welding. However, the surfaces of the extruded shape membersimmediately after the welding do not become smooth because uncutportions remain. In this way, when the plurality of extruded shapemembers are butt-joined together by welding, friction stir welding, andthe like, the protruding joint projections remain on the surfaces of theextruded shape members. The joint projections of the surfaces of theextruded shape members are smoothly manufactured by a manual operationusing a grinder.

The operation of smoothing the surfaces of the extruded shape members istroublesome because it is a manual operation using a grinder. Further, aconventional smoothing operation is an operation that require skillsbecause grinding should be performed in consideration of finishedsurfaces of the extruded shape members. Further, since the conventionalsmoothing operation requires much time and chip cuts are produced, theoperation environment is bad.

Separately from the operation of smoothing the surfaces of the extrudedshape members, an example in which surface manufacturing is performed ona plate member by mechanical devices is known in the Japanese PatentLaid-open No. 2000-158310 (Patent Document 1). Patent Document 1discloses a deburring machine which performs deburring of a hollowportion caused by a turret punch and the like. However, finishing thejoint projection continuously formed on the surfaces of theabove-mentioned extruded shape members efficiently in a short time isnot considered in this deburring machine.

Meanwhile, Japanese Patent No. 3070735 (Patent Document 2) discloses anexample in which, when a plurality of extruded shape members are joinedtogether by friction stir welding, a rear portion of a tool for frictionstir welding is provided with a cutting device which cuts a jointprojection. In this cutting device, an end mill is illustrated as anexample of a cutting tool. When the joint projection is cut using theend mill, it is difficult to perform cutting while the tip of the endmill is caused to move along the surfaces of the extruded shape membersaccurately. Specifically, the total length of the side structureconstructed by joining the plurality of extruded shape members togetheris as long as about 17 m to 25 m, and the width thereof is about 3 m.When cutting manufacturing is performed with the side structureconstrained, in order to maintain the surface of the side structure in aflat state, a constraint device with high accuracy is needed on a largescale. Further, in order to cause a cutting means, such as an end mill,which cuts a joint projection on the surface of the side structure, acomplicated control mechanism is required to move to follow the surfaceof the side structure accurately. For this reason, when the jointprojection of the side structure and the like is automatically cut, itshould be manufactured, leaving a cutting stock for finishing inconsideration of cutting accuracy. In addition, finishing manufacturingshould be performed on the cutting stock remaining on the surfaces ofthe extruded shape members by a manual operation using a grinder aspreviously mentioned.

SUMMARY OF THE INVENTION

The object of the present invention is to cut a joint projection formedon surfaces of extruded shape members by welding, friction stir welding,and the like, in a short time with high accuracy.

The object of the present invention can be achieved by a shape membermanufacturing apparatus comprising a carrier movable along a jointprojection of shape members and a milling cutter device installed on thecarrier for cutting the joint projection of the shape members, wherein amilling cutter of the milling cutter device is formed so as to be awayfrom surfaces of the shape members, as its milling surface approachesends of the milling cutter in the direction of its rotation axis, andthe milling cutter device is installed on the carrier to be movable inthe axial direction of the milling cutter.

Further, the object of the present invention can be achieved by a shapemember manufacturing method comprising the steps of constraining andpositioning the shape members where joint projection is continuouslyformed in a longitudinal direction of the shape members on a surface ofa joint obtained by joining a plurality of the shape members together,disposing a milling cutter device comprising a curved milling surfacehaving its widthwise central portion bulged toward the shape members soas to cut the joint projection of the shape members, cutting the jointprojection in the longitudinal direction of the shape members in a statein which the widthwise central portion of the milling surface of themilling cutter is caused to conform to one widthwise end of the jointprojection, and cutting the joint projection in the longitudinaldirection of the shape members in a state in which the widthwise centralportion of the milling surface of the milling cutter is caused toconform to the other widthwise end of the joint projection.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view showing an embodiment of a shape membermanufacturing apparatus of the present invention;

FIG. 2 is an enlarged front view of a support 30 of FIG. 1;

FIG. 3 is an enlarged front view of a support 40 and a support 60 ofFIG. 1;

FIG. 4 is a front view of a milling cutter device 80;

FIG. 5 is a side view of the milling cutter device 80;

FIG. 6 is a side view of a grinding device 90;

FIG. 7 is a front view of the grinding device 90;

FIG. 8 is an explanatory view showing a grinding surface of a grindingbelt; and

FIG. 9 is an explanatory view showing a cutting situation of a millingcutter 81.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, the present invention will be described with reference toFIG. 1 to FIG. 9. FIG. 1 is a front view showing an embodiment of ashape member manufacturing apparatus according to the present invention.FIG. 2 and FIG. 3 are front views showing a situation in which a sidestructure is positioned and constrained by a shape member manufacturingapparatus shown in FIG. 1 while it is manufactured. FIG. 4 and FIG. 5are explanatory views of a driving part of a milling cutter device.FIGS. 6 to 8 are explanatory views of a grinding device. FIG. 9 is anexplanatory view showing a detailed structure of a milling cutter of themilling cutter device.

In FIG. 1, a side structure 8 is placed and constrained on the shapemember manufacturing apparatus with the outer surface of the car upward.A plurality of mounts 11 are installed on a bed 10 at predeterminedintervals (for example, an interval of about 1 m to 2 m) in alongitudinal direction of the side structure 8 (hereinafter referred toas an X-axis direction) Each mount 11 is disposed so that itslongitudinal direction directs toward a widthwise direction of the sidestructure 8 (hereinafter referred to as a Y-axis direction). The totallength of each mount 11 is set to be longer than the width dimension ofthe side structure 8. A support 30, a support 40 and a support 60 areattached on an upper surface of each mount 11. When the side structure 8is seen from the X-axis direction, it has a curved shape bulged upward.In FIG. 1, a left end of the side structure 8, that is, an upper portionconnected to a roof structure when a car body is constructed issupported by the support 30. A right end of the side structure 8, thatis, a lower portion connected to an underframe when a car body isconstructed is supported by the support 40. The side structure 8 has itscentral portion in the Y-axis direction supported by the support 60. Thesupport 30, the support 40, and the support 60, which are installed oneach of the plurality of mounts 11, support the own weight of the sidestructure 8 and manufacturing load for manufacturing the surface of theside structure.

As shown in FIG. 2, the upper portion of the side structure 8 has ashape which is curved inwardly in the widthwise direction of the carbody. The support 30 comprises a pushing jig 31 having a curvedsupporting surface that conforms to the curved outer surface of the carof the upper side of the side structure 8. With the curved supportingsurface of the pushing jig 31 pushed against the outer surface of thecar of the side structure 8, the pushing jig 31 is fixed to the support30 by a fixing jig 32. The pushing jig 31 pushes the side structure 8against a horizontal supporting surface of the support 30, and pushesthe side structure 8 toward the support 40. The support 30 is fixed tothe mount 11 with a fixing means, such as bolts. The curved supportingsurface of the pushing jig 31 has a shape which conforms to the shape ofthe outer surface of the car, for example, of the side structure, theroof structure, or the like, as members to be constrained. A backingplate such as an aluminum alloy plate is installed between thesupporting surface of the support 30 and the side structure 8. Thebacking plate is installed for preventing the side structure 8 frombeing scratched.

The support 40 comprises a supporting jig 41 a having an L-shapedsupporting surface which supports the lower portion of the sidestructure 8. The supporting jig 41 a is put on a rest 41. The supportingjig 41 a moves so as to be capable of advancing or retreating in theY-axis direction on the rest 41 by a pusher 43. The supporting jig 41 ais made of an aluminum alloy, and is disposed so as not to scratch theside structure 8. The supporting jig 41 a bears the side structure 8which has been pushed toward the support 40 by the pushing jig 31. Thepushing jig 31 and the supporting jig 41 a perform the positioning ofthe side structure 8 in the Y-axis direction. The side structure 8 ispushed against the supporting jig 41 a by a hold down link 42 fromabove. The holddown link 42 is installed on the rest 41. The rest 41 issupported to move up and down by means of a screw jack 44. The height ofthe rest 41 is adjusted by the screw jack 44. The screw jack 44comprises a vertically arranged screw rod 46, and the rest 41 isinstalled on an upper end of the screw rod 46. The screw jack 44 isinstalled in each of the plurality of mounts 11. The screw jacks 44installed in the respective mounts 11 are connected to each other by acoupling shaft 45. As the coupling shaft 45 is driven, the respectivescrew jacks 44 interlock with each other to adjust the height of therespective rests 41. A worm gear is installed in the coupling shaft 45,and engages with a worm wheel that constitutes the screw jack 44. Ascrew rod 46 is screwed to the worm wheel. Accordingly, when thecoupling shaft 45 is rotated, the worm gear rotates the worm wheel toraise or lower the screw rod 46. The coupling shaft 45 is installedsubstantially over the entire length of the bed 10. An electric motorthat drives the coupling shaft 45 is installed adjacent to the screwjack substantially at a central position of the bed 10 in the X-axisdirection.

A guide rod 47 is installed parallel to the screw rod 46, and the rest41 is fixed to an upper end of the guide rod 47. The guide rod 47 issupported to be slidable up and down by a guide 48, and has a functionto guide the screw rod 46 vertically.

The screw jack 44 and the guide 48 are installed on a movable carriage50 and constitute the support 40. The movable carriage 50 is installedto be movable in the Y-axis direction on the mount 11. Anextension/retraction device 52 moves the movable carriage 50 in theY-axis direction, and adjusts the position of the support 40 accordingto the width dimension of the side structure 8. The extension/retractiondevice 52 has a screw jack built therein, and is installed on each ofthe plurality of mounts 11. Each extension/retraction device 52installed on each of the mounts 11 is coupled with an interlocking shaft53. As the interlocking shaft 53 is driven, similar to the screw jack44, the respective extension/retraction devices 52 interlock with eachother to adjust the positions of the respective supports 40 in theY-axis direction.

The support 60 is installed on each of the plurality of mounts 11, andsupports the side structure 8 from the inside of a car. The support 60is installed between the support 30 and the support 40. The basicstructure of the support 60 is similar to the support 40, and asupporting jig 61 a is installed on a rest 61. In the side structure 8,joints of a plurality of extruded shape members have higher strengththan the other portions. The supporting jig 61 a supports the joints ofthe plurality of extruded proportions that constitutes the sidestructure 8 from the inside of a car. The rest 61 is supported to bemovable up and down by a screw rod 66 and a guide rod 67. The screw rod66 constitutes the screw jack 64. The screw jack 64 is coupled withanother jack 64 of an adjacent support 60 by a coupling shaft 65. Theguide rod 67 is supported to be slidable up and down by a guide 68, andhas a function to guide the screw rod 66 vertically. The screw jack 64and the guide 68 are installed on a movable carriage 70, and constitutethe supports 60. The movable carriage 70 is installed to be moveable onthe mount 11 in the Y-axis direction. The position of the movablecarriage 70 in the Y-axis direction is adjusted by means of anextension/retraction device 72 having a screw jack built therein. Theextension/retraction device 72 is coupled with the extension/retractiondevice 72 of an adjacent movable carriage 70 by an interlocking shaft73.

Next, a manufacturing means that performs cutting and grinding of theouter surface of the car of the side structure 8 will be described. InFIG. 1, rails 101 are respectively installed along the X-axis directionon an upper surface of the bed 10 at both side positions of each mount11 in its longitudinal direction, that is, in the Y-axis direction. Acarrier 100 travels on the two rails 101 in the X-axis direction. Thecarrier 100 is composed of two legs 102 installed on both sides in theY-axis direction and a girder 103 that connects the two legs 102 witheach other. The longitudinal direction of the girder 103 is disposedalong the Y-axis direction. Four columns 105 are installed in the guider103, and the columns 105 are installed to be movable in the Y-axisdirection with respect to the girder 103. A milling cutter device 80 anda grinding device 90 are respectively installed in each column 105. Eachcolumn 105 is disposed in the Y-axis direction of each girder 103 so asto conform to the joining positions between extruded shape members of aworkpiece, for example, the side structure 8, which is constrained onthe mount 11. Each column 105 is installed so that it can ascend ordescend with respect to the girder 103. The milling cutter device 80 andthe grinding device 90 are installed at the lower end of the respectivecolumn 105. When the milling cutter device 80 and the grinding device 90manufacture the outer surface of the car of the side structure 8, therespective column 105 is positioned at optimal positions. The millingcutter device 80 and the grinding device 90, which are set in therespective column 105, are juxtaposed to each other in the X-axisdirection, and are disposed along joining lines between the extrudedshape members of the side structure 8. The milling cutter device 80 andthe grinding device 90 are installed to be rotatable about the verticalaxis of the column 105. Accordingly, the arrangement of the millingcutter device 80 and the grinding device 90 can be switched according tothe situation of movement of the carrier 100 in the X-axis direction.The position adjustment of each column 105 in the Y-axis direction isperformed by automatic control such that a joint projection of the sidestructure is detected using an optical sensor, and the manufacturingpositions of the milling cutter device 80 and the grinding device 90,which will be described later, are caused to conform to the jointprojection.

In addition, the joint projections of the side structure 8 constructedby extruded shape members are located at predetermined positions in theY-axis direction and extend continuously in the X-axis direction.Accordingly, the position adjustment of each column 105 in the Y-axisdirection may be manually performed without using the optical sensor.Otherwise, position data about the joint projection of the sidestructure 8 in the Y-axis direction may be stored in advance in acontrol device, and the position adjustment of each column 105 in theY-axis direction may be performed on the basis of the position data.

Further, the milling cutter device 80 and the grinding device 90 aresupported by tilt columns 105 b and 105 d which are installed such thatthey can be tilted about the X-axis as its rotation center with respectto each column 105. The upper portion, that is, the left portion of FIG.1 of the side structure 8 has a shape which is curved toward the centerof a car, and a support structure which can make the milling surface ofthe milling cutter device 80 and the grinding surface of the grindingdevice 90 conform to each other.

In the present embodiment, the four columns 105 are installed in theY-axis direction, but they may be installed in accordance with joiningspots of the side structure 8 as a workpiece. The number of columns 105to be installed is not limited to the present embodiment.

Next, a detailed structure of the milling cutter device 80 will bedescribed. As shown in FIG. 4 and FIG. 5, the milling cutter device 80is installed in the tilt column 105 b so that the tilt of its millingsurface can be varied according to that of the surface of a workpiece.The tilt column 105 b is supported by a tilt rotation shaft 105 c whoserotation center is disposed in the X-axis direction. The milling cutterdevice 80 mainly comprises a milling cutter 81, an electric motor 82which drives the milling cutter 81, and a cylinder unit 89 which adjuststhe height of the milling cutter 81. A pulley 81 a is installed at oneend of the rotating shaft 81 b which supports the milling cutter 81. Atiming belt 83 is installed between a pulley 82 a installed on therotating shaft of the electric motor 82 and the pulley 81 a. Therotating shaft 81 b and the electric motor 82 are installed in the slideframe 84. The slide frame 84 is installed to be slidable up and downwith respect to the tilt column 105 b. The cylinder unit 89 is installedin the upper portion of the tilt column 105 b, and the slide frame 84 isattached to a tip of a telescopic shaft of the cylinder unit 89. Thecylinder unit 89 moves the slide frame 84 up and down, to adjust theposition of the milling cutter 81 with respect to the side structure 8as a workpiece. The milling cutter 81 is pushed against a workpiece toperform cutting, according to weights of respective members installed onthe slide frame 84. At this time, the adjustment of a pushing force ofthe milling cutter 81 can be performed by adjusting the pressure of acompressed air supplied to the cylinder unit 89.

A support arm 81 c that supports the rotating shaft 81 b providing thesupport of the milling cutter 81 is installed at a lower end of theslide frame 84. Sliding plates 85 are respectively installed on axiallylateral sides of the milling cutter 81 on a bottom surface of thesupport arm 81 c. Each sliding plate 85 has a predetermined length inthe X-axis direction. When the surface of the side structure 8 is cutusing the milling cutter 81, the sliding plate 85 keeps the gap betweenthe milling cutter 81 and a manufacturing surface constant. Further, adust-collecting cover 97 is installed in the support arm 81 c forcovering the surroundings of the milling cutter 81. The dust-collectingcover 97 is provided with a connecting barrel 86 connected to adust-collecting duct. Chips that are produced when the milling cutter 81cuts joint projection on the surface of the side structure 8 is suckedby a dust collector installed in the dust-collecting duct.

Next, the relationship between the milling cutter 81 and the sidestructure 8 as a workpiece will be described with reference to FIGS. 9Aand 9B. An example of the side structure 8 shown in FIG. 9 is a jointobtained by joining two extruded shape members 8C and 8D togetherthrough friction stir welding. A joint projection 8B is formed at anabutting portion of the two protruded shape members 8C and 8D on the carbody surface. The joint projection 8B, as shown in FIG. 9A, remainsafter joined. In addition, the surfaces of the extruded shape members 8Cand 8D shown in FIG. 9 in the Y-axis direction are substantially flatlyformed except for the joint projection.

FIGS. 9A and 9B show a state of the milling cutter 81 as seen from theX-axis direction. The milling surface of the milling cutter 81 thatperforms cutting is formed in a circular-arc shape, and the center ofthe circular arc is located at the central position of the millingcutter 81 in its widthwise direction, that is, in the Y-axis direction.The radius of the circular arc is, for example, about 800 mm.Accordingly, the widthwise both side portions of the milling surface ofthe milling cutter 81 have a smaller diameter than the central portion.The rotation axis of the milling cutter 81 can be tilted at an angle of↓1 (+0.3°) or θ2 (−0.3°) with respect to the surface of the sidestructure 8. That is, the milling cutter device 80 is tilted and themilling surface of the milling cutter 81 is tilted by rotating the tiltcolumn 105 b with respect to the tilt rotation shaft 105 c. This tiltangle is determined depending on the magnitude of the radius of thecircular arc of the milling surface. The tilt center in the case oftilting the milling cutter 81 is on the side of the extruded shapemembers 8C or 8D. Therefore, the milling cutter 81 is tilted at theangle of θ1 or θ2, to thereby move the position where the milling cutter81 performs cutting in the Y-axis direction.

The sliding plates 85 each are installed at the both side positions ofthe milling cutter 81 in the Y-axis direction. When the milling cutter81 is tilted, one sliding plate 85 is disposed in contact with theextruded shape members 8C or 8D. For example, as shown in FIG. 9A, whenthe milling cutter 81 is tilted at the angle of θ1 toward the extrudedshape member 8D, the left sliding plate 85 in the figure makes contactwith the surface of the extruded shape member 8D to maintain thedistance between the milling surface and the extruded shape member. Asshown in FIG. 9B, when the milling cutter 81 is tilted at the angle ofθ2 toward the extruded shape member 8C, the opposite sliding plate 85 isdisposed in contact with the extruded shape member 8C. Then, the millingcutter cuts uncut portions remaining after the cutting operation in FIG.9A. Accordingly, the contact surfaces of the two sliding plates 85 withextruded shape members are tilted with respect to the centerline ofrotation of the milling cutter 81. Further, while the milling cutter 81cuts the joint projection 8B, each of the sliding plates 85 is disposedto make contact with the surface of the extruded shape member to keepthe cutting depth of the milling cutter 81 constant. Each of the slidingplates 85 prevents the milling cutter 81 from excessively deeply cuttingthe joint projection of the extruded shape members 8C and 8D.

The width of the milling cutter 81 is set to be slightly wider than awidth dimension L1 of the joint projection. A small gap is providedbetween the milling cutter 81 and each of the sliding plates 85. Thewidth of the milling cutter is arranged to be a little wider than thatof the joint projection. As shown in FIGS. 9A and 9B, since cutting isperformed in a tilted state, the entire joint projection cannot be cutin one cutting process. Accordingly, the milling cutter 81 reciprocatesin the X-axis direction on the joint projection, thereby cutting theentire joint projection. In the state shown in FIG. 9A, up-cutting ofthe milling cutter 81 is performed because a portion of the jointprojection to be cut is large. In the state shown in FIG. 9B,down-cutting of the milling cutter 81 is performed because an uncutportion of the joint projection is small, and the moving speed of themilling cutter in the X-axis direction is increased. In this manner, themilling cutter 81 is reciprocated once in the X-axis direction to cutthe joint projection, but in the state shown in FIG. 9B, the movingspeed of the milling cutter in the X-axis direction is increased toshorten the cutting time.

Meanwhile, although the milling cutter 81 has been described in relationto an example in which the surface of the extruded shape member 8C or 8Dis substantially flatly formed, the car body surface of the sidestructure 8 in the Y-axis cross shape member also has a portion whichforms a curved surface protruding toward the outer side of the car. At ajoint between extruded shape members that form the curved surface inthis manner, a milling surface of a milling cutter may be formedparallel to its rotation axis. In this case, similarly, the millingcutter is tilted (at an angle of θ1 or θ2) to perform cutting. Further,the milling cutter 81 has one circular arc as the shape of its millingsurface. However, it can also be contemplated that a widthwise centralportion of a milling cutter is formed in a predetermined radius of acircular arc, and that its widthwise both ends are formed in a circulararc having a smaller radius than the central portion.

As described above, the milling surface of the milling cutter 81 isconfigured to be gradually away from the surfaces of the extruded shapemembers to be cut, as it goes toward both sides in the Y-axis directionrelative to the surfaces of the extruded shape members. Therefore, onthe milling surface of the milling cutter 81, the widthwise(Y-axis-direction) central portion of the milling cutter 81 deeply cutsthe surfaces of the extruded shape members. Accordingly, as mentionedabove, cutting is performed while the milling cutter 81 is tilted, eachof the sliding plates 85 installed on the both sides of the millingcutter 81 is brought into contact with the extruded shape member 8C or8D, and the distance between the milling cutter 81 and each of extrudedshape members 8C and 8D is kept constant. This can prevent the millingcutter 81 from excessively deeply cutting the surfaces of the extrudedshape members 8C and 8D. The joint projection can be cut with thesliding plate 85 brought into contact with the extruded shape member, tothereby cut the surfaces of the extruded shape members with highaccuracy. Further, in the above cutting, any failure does not occur evenif the cutting operation is automated because cutting is performed sothat the sliding plates 85 make a milling cutter follow the surfaces ofthe extruded shape members. The automation of cutting operation makes itpossible to perform cutting efficiently in a short time as compared to amanual operation.

Meanwhile, as mentioned above, the milling cutter can be moved in theY-axis direction to cut the surfaces of the extruded shape memberswithout being tilted, as long as the milling cutter can be moved in theX-axis direction along the surfaces of the extruded surfaces withoutusing the sliding plates 85. For example, a contact sensor or anon-contact sensor using light is installed in the vicinity of themilling cutter for detecting the deflection of the surfaces of theextruded shape members. The amount of the deflection of the surfaces ofthe extruded shape members detected by the sensor is adopted as inputvalues for controlling the vertical movement of the milling cutter, tomove the milling cutter along the surfaces of the extruded shapemembers. The milling surface of the milling cutter is formed in such ashape that its widthwise central portion is bulged further toward thesurfaces of the extruded shape members than the widthwise both sideportions. The central portion and both side portions of the millingsurface are formed in a shape connected by a smooth curved surface.Accordingly, when the joint projection of the surfaces of the extrudedshape members is cut, cutting is performed with the widthwise centralportion of the milling cutter conformed to one end portion of the jointprojection in the Y-axis direction. At this time, since uncut portionsremain at the other end portion of the joint projection in the Y-axisdirection, cutting is performed with the widthwise central portion ofthe milling cutter conformed to the other end portion of the jointprojection. In this way, the milling cutter is moved in the Y-axisdirection in response to the width of the joint projection, therebycutting the joint projection of the surfaces of the extruded shapemembers. In this case, any groove or depression does not remain becausethe opposite ends of the joint projection in the Y-axis direction can becompletely cut by the widthwise central portion of the milling cutter.Further, any seemingly noticeable groove or bump is not produced on thesurface of a cut portion because the widthwise both end portions of themilling surface of the milling cutter gradually retreat relative to thesurfaces of the extruded shape members. Accordingly, cutting can beperformed using such a milling cutter, thereby manufacturing thesurfaces of extruded shape members while improving the appearancethereof.

Next, the detailed structure of the grinding device 90 will be describedwith reference to FIG. 6 and FIG. 7. The grinding device 90 is abelt-type grinding device that uses a grinding belt 91. The grindingdevice 90 mainly comprises the grinding belt 91, an electric motor 92,and a plurality of pulleys. The main parts including the electric motor92 are attached to a slide frame 95. The slide frame 95 is attached soas to be slidable up and down with respect to a tilt column 105 d. Acylinder unit 99 is installed at an upper end of the tilt column 105 d,and the slide frame 95 is attached to a tip of a telescopic shaft of thecylinder unit 99. The cylinder unit 99 moves the slide frame 95 up anddown, to thereby adjust the position of a grinding surface of thegrinding belt 91 with respect to the side structure 8 as a workpiece.The grinding belt 91 that is an endless belt is rotatably supported bypulleys 93 a, 93 b, and 93 c which are arranged in a triangular shape asseen from the Y-axis direction. The pulley 93 a is provided with adriving pulley for receiving power from the electric motor 92. A timingbelt 96 for transmitting a driving force is hung between the drivingpulley and the pulley 94 installed in the electric motor 92. In thegrinding belt 91, a base of a triangle that is formed by the threepulleys is tensioned by the pulley 93 a and the pulley 93 b, therebyforming a flat grinding surface. The grinding surface extends toward Xaxis of the side structure 8 at an angle to be described later. Holddownpulleys 96 a and 96 b are installed between the pulley 93 a and thepulley 93 b to push the grinding belt 91 against a manufactured surfaceof the side structure 8 as a workpiece. A dust-collecting cover 97 isinstalled around an outer peripheral portion of the grinding belt 91.The dust-collecting cover 97 is provided with a connecting barrel 98 forconnection to a dust collector and a dust-collecting duct.

Next, the situation of the grinding surface of the grinding belt 91 inthe grinding device 90 will be described with reference to FIG. 8. InFIG. 8, as mentioned above, the grinding belt 91 is stretched by thepulley 93 a and the pulley 93 b. The grinding belt 91 stretched by thetwo pulleys is installed to extend at a tilt angle θ3 (about 10°). Aportion of the grinding belt 91 that is pushed against the sidestructure 8 by the holddown pulleys 96 a and 96 b constitutes a grindingsurface. The width of the grinding surface is L3 and slightly wider thanthe width of a workpiece to be cut by the milling cutter device 80.Further, the width L3 of the grinding surface is set to be wider thanthe width L1 of the joint projection 8B of the side structure 8.

Next, the manufacturing situation of the side structure 8 by means ofthe shape member manufacturing machine will be described. First, asshown in FIG. 1 to FIG. 3, the side structure 8 is positioned andconstrained on the supports 30, 40, and 60 of each mount 11. Next, thecarrier 100 is disposed at an end portion of the side structure 8 in theX-axis direction, and each of the columns 105 is arranged to correspondto each joint of respective extruded shape members. At this time, thetilt of the tilt column 105 b of each column 105 is adjusted, to therebydispose the milling surface of the milling cutter 81 so as to be tiltedat the angle θ1 with respect to the joint projection 8B of the surfacesof the extruded shape members. In this state, the milling cutter 81 islowered by the cylinder unit 89 while the milling cutter 81 is rotated,thereby starting cutting the joint projection 8B. When one sliding plate85 makes contact with the surface of the extruded shape member, thedescent of the milling cutter 81 stops, the carrier 100 is moved in theX-axis direction, and then the joint projection 8B of the surface of theside structure 8 is cut.

The milling surface of the milling cutter 81 is formed in a circulararc, and the milling cutter performs cutting while being tilted by theangle θ1 with respect to the surfaces of the extruded shape members.Therefore, the cutting width of the milling cutter 81 is slightlynarrower than the width L1 of the joint projection. Accordingly, asshown in FIG. 9A, the milling cutter 81 is pulled over to one side (leftside in the figure) of the joint projection 8B, and a left portion ofthe joint projection 8B is mainly cut. In this state, the carrier 100travels in the X-axis direction from one end of the side structure 8toward the other end thereof. At this time, the milling cutter 81 cutsthe joint projection through up-cutting. When the carrier 100 hasreached the other end of the side structure 8, the milling cutter 81 istilted by the angle θ2 to the opposite side. Moreover, with the cuttingposition of the milling cutter 81 conformed to a right end of the jointprojection 8B, the carrier 100 is moved in the direction reverse to theprevious process, and then the remaining portion of the joint projection8B is cut. At this time, the sliding plate 85 located on the right sideof the milling cutter 81 makes contact with the surface of the extrudedshape member, to keep the spacing between the milling cutter 81 and theextruded shape member. Then, the milling cutter 81 cuts the rightportion of the joint projection 8B through down-cutting. When thecarrier 100 has reached one end of the side structure 8, the cutting ofthe joint projection 8B is completed.

Next, the grinding device 90 is positioned in a grindable state at aportion of the joint projection 8B for which cutting has been completed.Then, while the grinding belt 91 is rotated and grinded by pushing itsgrinding surface against the surfaces of the extruded shape members, thecarrier 100 is moved from one end of the side structure 8 toward theother end thereof to perform grinding. At a point of time when thecarrier 100 has reached the other end of the side structure 8, the jointprojection is flatly manufactured with improved appearance.

In this manner, the shape member manufacturing apparatus cuts and grindsthe joint projection of the side structure 8. Since the milling surfaceof the milling cutter 81 is formed in a circular arc, the radius of thewidthwise both ends of the milling surface is formed to be smaller thanthat of the widthwise central portion. Therefore, a noticeable groove isnot formed on the surface of a workpiece because the surface of theworkpiece is not cut by the widthwise ends of the milling surface of themilling cutter 81 during its normal cutting operation. Accordingly, whenthe milling cutter 81 cuts a joint projection, the appearance of thesurfaces of the extruded shape members can be improved.

Since the milling cutter 81 removes the joint projection 8B at theabutting portion of the two extruded shape members through two cuttingprocesses, both side corners of the joint projection 8B in the Y-axisdirection can be completely removed.

Meanwhile, the milling cutter 81 is an example which performs cuttingmanufacturing in the case in which the surfaces of the respectiveextruded shape members 8C and 8D of the side structure 8 as a workpiecehave a flat shape. A milling cutter installed in the leftmost column 105shown in FIG. 1 has a flat milling surface, that is, a milling surfaceparallel to the rotation axis of the milling cutter. The extruded shapemembers constituting the side structure 8 to be cut by the millingcutter have a shape sectional shape in the Y-axis direction that isformed in a shape of a curved surface protruding toward the outer sideof the car. Accordingly, even if the milling surface of the millingcutter is flat, the widthwise both ends of the milling surface arelocated at positions relatively away from the surfaces of the extrudedshape member than the widthwise central portion. Therefore, the cornersat the widthwise ends of the milling surface do not cut the surfaces ofthe extruded shape members. When a outer surface of the car of a sidestructure 8 has a sectional shape which is curved toward the outer sideof the car, the appearance of the surfaces of the extruded shape memberscan be prevented from deteriorating, even if the milling surface of themilling cutter has a flat shape.

The joint projection of the plurality of extruded shape membersconstituting the side structure 8 extends in the X-axis direction. Thegrinding device 90 performs grinding with the longitudinal direction ofthe grinding surface of the grinding belt 91 tilted by the angle θ3 withrespect to the X-axis direction. Accordingly, the grinding surface isnot partially worn due to the shape of the joint projection because thegrinding surface of the grinding belt 91 performs grinding while movingin a tilted direction. Since the grinding surface of the grinding belt91 is not partially worn, the surfaces of the extruded shape members canbe grounded evenly. Therefore, the appearance of the surfaces of theextruded shape members can be improved.

As described above, the surfaces of the extruded shape members can bemanufactured smoothly by cutting and grinding the joint projection ofthe extruded shape members using the milling cutter device and grindingdevice that are presented in the embodiment of the present invention.Further, any groove that may deteriorate the appearance of the surfacesof the extruded shape members will not be formed on the surfaces of theextruded shape members. When a side structure is manufactured using theextruded shape members and when the surface of the side structure issubjected to hairline processing without any coating, the appearance ofthe surface of the side structure can be improved.

Since the milling cutter device and the grinding device each areequipped with the dust-collecting cover, and since chips and powder dustcan be collected by a dust collector, operation environment can beprevented from deteriorating.

According to the shape member manufacturing apparatus, a jointprojection which is formed when a plurality of shape members are joinedtogether can be cut and ground in a short time with high accuracy.

1. A shape member manufacturing method comprising the steps ofconstraining and positioning shape members where a joint projection iscontinuously formed in a longitudinal direction of the shape members ona surface of a joint obtained by joining a plurality of the shapemembers together, disposing a milling cutter device comprising a curvedmilling surface having its widthwise central portion bulged toward theshape members so as to cut the joint projection of the shape members,cutting the joint projection in the longitudinal direction of the shapemembers in a state in which the widthwise central portion of the millingsurface of the milling cutter is caused to conform to one widthwise endof the joint projection and cutting the joint projection in thelongitudinal direction of the shape members in a state in which thewidthwise central portion of the milling surface of the milling cutteris caused to conform to the other widthwise end of the joint projection.2. The shape member manufacturing method according to claim 1, wherein adirection that the milling cutter device moves when cutting one end ofthe joint projection and a direction that the milling cutter devicemoves when cutting the other end of the joint projection are reverse toeach other.
 3. The shape member manufacturing method according to claim1, wherein the milling cutter device cuts the one end of the jointprojection of the shape members through up-cutting, and cuts the otherend of the joint projection of the shape members through down-cutting.4. The shape member manufacturing method according to claim 1, wherein asurface of a cut portion of the shape members is ground after thecompletion of the cutting of the one end and other end of the jointprojection of the shape members.